近断层地震动下多跨简支梁桥地震响应及减震研究  

Study on seismic responses and mitigation of multi-span simply supported beam bridges under near-fault ground motions

作　　者：李旺平 杨雄 焦应乾 裴银海 石岩[1] LI Wang-ping;YANG Xiong;JIAO Ying-qian;PEI Yin-hai;SHI Yan(School of Civil Engineering,Lanzhou University of Technology,Lanzhou 730050,China)

机构地区：[1]兰州理工大学土木工程学院,甘肃兰州730050

出　　处：《兰州理工大学学报》2024年第4期103-111,共9页Journal of Lanzhou University of Technology

基　　金：国家自然科学基金(51908265,51768042)。

摘　　要：为研究近断层地震动下多跨简支梁桥的地震响应及其减震措施,以1座4跨简支梁桥为研究对象,选取3组分别考虑滑冲效应、向前方向性效应及无脉冲效应的近断层地震动和1组远断层地震动作为输入,分析主梁、桥墩和支座等的响应和损伤.发现速度脉冲型近断层地震动对桥梁纵横向的位移均有放大作用,既会增加桥墩和支座的损伤程度,也会增加梁间纵向碰撞次数和碰撞力峰值.为此提出“防屈曲支撑(BRB)+粘滞阻尼器”的组合减震系统,并对粘滞阻尼器的布置形式和参数对减震效果的影响进行了分析.结果表明:该减震方案可有效降低桥墩和支座的损伤、减小主梁纵向位移;且阻尼器布置在主梁与桥台间更有利于减震控制;建议粘滞阻尼系数C梁间取3 000 kN·s/m,台梁间取4 000 kN·s/m,速度相关系数α取0.4.In order to study the seismic response and mitigation measures of a multi-span simply suppor-ted beam bridge under near-fault ground motion,a 4-span simply supported beam bridge was taken as theresearch object.Three groups of near-fault ground motions were selected,which respectively considerfling step effect,forward directivity effect,and no pulse effect,along with one group of far-fault seismicmotions for comparison.The seismic response and damage degree of key components such as main beams,piers,and bearings.It was found that the velocitypulse-type near-fault ground motion amplifies the displacement response in both longitudinal and trans-verse bridges,which not only increases the damage degree of the piers and bearings,but also increases thenumber of longitudinal collisions between beams and the peak value of collision force.Therefore,a com-bined seismic reduction system of Buckling-Restrained Brace(BRB)and viscous damper was put forward.The influence of the arrangement and parameters of a viscous damper on the seismic reduction effect is an-alyzed.The results show that the mitigation scheme effectively reduces the damage to piers and bearingsand reduces the longitudinal displacement of main beams.Arranging dampers between the main beam andits abutment is more conducive to the seismic control of a multi-span simply supported beam bridge.It issuggested that the viscous damping coefficient C between the main beams should be 3000 kN·s/m,whilethe viscous damping coefficient C between abutment and main beams should be 4000 kN·s/m,with thevelocity correlation coefficient a of 0.4.

关 键 词：简支梁桥 近断层地震动 地震响应 组合减震系统 损伤控制 

分 类 号：U448.21[建筑科学—桥梁与隧道工程]